Personal portable power supplies are known which can be easily carried by a person to provide auxiliary power for the starting of automobiles with weak batteries or the playing of portable radios or televisions. Such a portable power supply is known from U.S. Pat. No. 5,589,292. This patent is hereby incorporated by reference. In this portable power supply, the operator is able to connect the portable power supply to the battery of an automobile engine to increase the starting power of the automobile battery. It is extremely useful on those occasions when a normally healthy battery is weakened due to extreme cold or prolonged discharge such as when the operator of the vehicle leaves electrical accessories such as headlights operating for prolonged periods of time without the engine running. The operator of the portable power supply can then hook the portable power supply to the battery of the vehicle to boost the power of the vehicle's battery and start the vehicle, thus allowing the vehicle's battery to recharge.
The operator of the portable power supply can also use the portable power supply to operate personal accessories such as radios for longer periods of time than the common dry cell batteries used in portable radios or when these portable devices are not near their normal source of power such as a car battery. The battery in these portable power supplies is preferably rechargeable so that they may be repetitively used.
When the portable power supply is used to start the engine of a motor vehicle, a large amount of current is needed over a very short time period. Traditional wet cell batteries, especially lead acid batteries are often used for this purpose. In particular sealed lead acid (SLA) batteries are the powered source of choice due to their ability to withstand rugged operating conditions such as over-charge and deep discharge, ease of maintenance, ability to withstand vibration and shock, and their capability of extended storage. Lead acid batteries which were developed in 1859, have conventionally been manufactured in 6 and 12 volt models. In SLA batteries, the amount of power depends on the battery chemistry and/or the number of battery plates. If a more powerful battery (higher discharge current) was desired to withstand extreme conditions, another battery with a larger ampere hour rating (capacity) would be used, for example a 20 amp per hour battery instead of a 15 ampere per hour battery. This would lead to a corresponding higher discharge current. This also leads to an increase in the size, weight and/or cost of the SLA battery.
Spirally wound batteries are known from U.S. Pat. No. 5,047,300 which is incorporated by reference. In this particular patent, thin film technology is used along with special terminal connectors to deliver a large amount of energy in a small time (power). If these thin metal film batteries are used in portable power supplies, they can provide a great deal of power to start an engine, however they discharge very rapidly due to low energy density (capacity) and the need to keep the size of portable device small. Thus, spiral wound batteries need to be recharged frequently. This can be inconvenient for the operator if he/she forgets to recharge the portable power supply between uses. Also the cost of thin metal film batteries is very expensive.